Explain why all the carbon dioxide concentration readings for area B are higher than for area A. - Edexcel - GCSE Biology - Question 3 - 2011 - Paper 1

In area B, not all of the plant material is consumed by the mouse or snake, leading to a larger amount of organic matter that undergoes decomposition, which produces carbon dioxide.

Additionally, the mouse in area B may respire more due to increased activity levels, releasing more carbon dioxide into the environment.